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Plant extracts comprise a complex mixture of numerous phytochemicals including important alkaloids and polyphenols that can reduce metal ions, and comprise unsaturated compounds such as α-linolenic and carboxylic acid that acts as stabilizing agents in the greener assembly of nanomaterials. The present study demonstrates the role of phytoconstituents from flowers of Tridax trilobata (T. trilobata) in the synthesis of silver nanoparticles (AgNPs) that investigates their effects on the growth and development of the silkworm Bombyx mori L. besides controlling the occurrence of Flacherie and Sappe microbial diseases. FTIR and 13C NMR spectral studies confirmed the in situ role of phytochemicals from the flower extract responsible for the reduction of silver ions to AgNPs with crystalline structure, which is confirmed by XRD analysis. Compared to pure alkaloids and polyphenols, AgNPs synthesized with crude flower extract displayed synergistic antibacterial activity against Flacherie and Sappe microbial strains such as B. subtilis, S. aureus, E. coli, B. cereus, Aerobactercloacae, and S. typhi. Furthermore, AgNPs prevented the growth of biofilms in a concentration-dependent manner and an increase in inhibition is observed with concentration augmentation from 0 to 50 µg/mL. In addition, the biosynthesized AgNPs increased the feeding efficiency and improved the body weight and shell weight of Bombyx mori L. larvae, pupae, and cocoons. Overall, this integrated study found that AgNPs were effective in reducing Flacherie and Sappe disease caused by the consumption of bacterially contaminated mulberry leaves, thus improving the survival rate of Bombyx mori L. and eventually improving the crop yield through insights into the anti-biofilm activity of phytochemical-adorned AgNPs.

We describe the synthesis, structure, and magnetic properties of two new perovskite oxides, Sr 4M 3ReO 12(M = Co, Fe), that exhibit ferromagnetism with fairly high ordering temperatures ( Tc= ∼250−300 K). While the M = Co phase crystallizes in a partially ordered double perovskite ( Fm3̅ m) structure ( a= 7.8153 Å), the M = Fe phase adopts a primitive cubic perovskite ( Pm3̅ m) structure ( a= 3.9353 Å), where the transition metal atoms are not ordered in the long range. Magnetization studies revealed bulk ferromagnetism for both oxides, but the disordered structures seem to preclude a long-range magnetic order and a definite Tc. While further studies are needed to establish the exact origin of magnetism of these materials, the present investigation reveals the possibility of designing new ferromagnetic oxides based on M 3+−O−Re 7+(M = Co, Fe) magnetic interaction in the perovskite related structures. [ABSTRACT FROM AUTHOR]

This study is aimed to recover the valuable metal ions from cathode materials of spent Li‒ion batteries (LIBs). Rapid microwave‒assisted dissolution process is investigated here to recover Li and Co from LiCoO 2 of spent LIBs. In the conventional method, about 6 h is required to extract about 90% of Li and Co using a mixture of citric acid (CA) and ascorbic acid (AA) at 80 °C. On the other hand, more than 85% of Li and Co was obtained in about 25 min by microwave (180 W)‒assisted dissolution. The dissolved Co and Li ions were precipitated, selectively: Li as LiHC 2 O 4 H 2 O or Li 2 CO 3 and Co as CoC 2 O 4 2H 2 O or Co‒citrate/ascorbate. The Co 3 O 4 was formed on heating the Co precipitate at 600 °C for 2 h. It is important to note that LiCoO 2 was re‒synthesized here by thermal decomposition of CoC 2 O 4 2H 2 O and LiHC 2 O 4 H 2 O at 750 °C for about 24 h. Thus, the microwave‒assisted hydrometallurgical method is found to be simple and rapid to recover Li and Co from spent LIBs., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

An effective and environmentally friendly recycling process designed for LiCoO 2 cathode powders of spent Li-ion batteries using mixture of mild organic acids, citric acid (CA), tartaric acid (TA) and ascorbic acid (AA), to recover the metals. Almost complete dissolution of Li and nearly 90% dissolution of Co occurred in at 80 °C for 6 h. The reducing agent, ascorbic acid (AA), converts the dissolved Co(III) to Co(II) thereby selective recovery of Co as Co(II)-oxalate is possible. The formation of Co(III)-and Co(II) complex is evident from the UV-Vis spectra of the dissolved solution as a function of dissolution time. Thus, the reductive-complexing dissolution mechanism is proposed here. These mild organic acids are environmentally benign unlike the mineral acids., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

New organic acid mixtures have been investigated to recover the valuable metal ions from the cathode material of spent Li-ion batteries. The cathodic active material (LiCoO2) collected from spent Li-ion batteries (LIBs) is dissolved in mild organic acids, iminodiacetic acid (IDA) and maleic acid (MA), to recover the metals. Almost complete dissolution occurred in slightly excess (than the stoichiometric requirement) of IDA or MA at 80°C for 6h, based on the Co and Li released. The reducing agent, ascorbic acid (AA), converts the dissolved Co(III)- to Co(II)-L (L=IDA or MA) thereby selective recovery of Co as Co(II)-oxalate is possible. The formation of Co(III)- and Co(II)-L is evident from the UV-Vis spectra of the dissolved solution as a function of dissolution time. Thus, the reductive-complexing dissolution mechanism is proposed here. These mild organic acids are environmentally benign unlike the mineral acids., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Nanomedicine is an emerging field concerned with the use of precision engineered nanomaterials, which leads to the development of novel remedial and diagnostic modalities for human use. In this study, Cu(NO 3 ) 2 and AgNO 3 precursors were reduced to copper nanoparticles (CuNPs) and silver nanoparticles (AgNPs) using Terminalia arjuna bark extracts under microwave irradiation in the presence of well-dispersed multi-walled carbon nanotubes (MWCNTs) in aqueous medium. The formation of CuNPs or AgNPs and their functionalization with MWCNTs via bioactive molecules of plant extract were evidenced from UV-Vis spectra, XRD, FTIR, FESEM, EDX, and TEM images. The phytochemically functionalized Cu-MWCNTs and Ag-MWCNTs nanomaterials showed enhanced biocide activity, and the inhibitory activity for bacteria was higher than that of fungus. Furthermore, these biohybrid nanomaterials are non-toxic to normal epithelial cells (Vero), whereas they are highly toxic for tested human cancer cells of MDA-MB-231, HeLa, SiHa, and Hep-G2. The cell viability was found to decrease with the increasing dose from 10 to 50 µg mL -1 , as well as incubation time from 24 to 72 h. For instance, the cell viability was found to be ~91 % for normal Vero cells and ~76 % for cancer cells for lower dose of 10 µg mL -1 .

Mappia foetida leaves extract is used as bioreductant for the synthesis of gold nanoparticles and their application in the efficient delivery of doxorubicin to human cancer cells is reported here. The formation of gold nanoparticles is evident from their characteristic optical absorption at ~560 nm. X-ray diffraction pattern of gold nanoparticles confirmed their fcc structure. Fourier transform infrared spectroscopy shows the bioactive molecules from plant extract capped on the surface of gold nanoparticles and conjugation of doxorubicin along with activated folic acid as navigational molecules for targeted drug delivery. Such a conjugation of gold nanoparticles is characterized by their weight loss, ~35-40 %, due to thermal degradation of plant biomass and conjugated drug along with receptor, as observed in thermogravimetric analysis. The spherical shaped gold nanoparticles (Φ 10-20 nm) are observed by field emission scanning electron microscopy and transmission electron microscopy images and the expected elemental composition by energy dispersive X-ray spectroscopy. Gold nanoparticles conjugated with activated folic acid and doxorubicin complex is found to be toxic for human cancer cells viz., MDA-MB-231, HeLa, SiHa and Hep-G2. Furthermore, the amount of drug released was maximum at pH 5.3 (an ambient condition for intravenous cancer drugs) followed by pH 7.2 and pH 6.8.

A green chemistry approach for the synthesis of Au, Ag and Au-Ag alloy nanoparticles (NPs) using the corresponding metal precursors and Jasminum sambac leaves extract as both reducing and capping media, under microwave irradiation, is reported. During the formation, as expected, the reaction mixture shows marginal decrease in pH and an increase in solution potential. The formation of NPs is evident from their surface plasmon resonance (SPR) peak observed at ∼555 nm for Au, ∼435 nm for Ag and ∼510 nm for Au-Ag alloy. The XRD pattern shows fcc structure while the FTIR spectra indicate the presence of plant residues adsorbed on these NPs. Such a bio-capping of NPs is characterized by their weight loss, ∼35% due to thermal degradation of biomass, as observed in TG analysis. The colloidal dispersion of NPs is stable for about 6 weeks. The near spherical shape of NPs (ϕ20-50 nm) is observed by FE-SEM/TEM images and EDAX gives the expected elemental composition. Furthermore, these NPs showed enhanced antimicrobial activity (∼1-4-fold increase in zone of inhibition) in combination with antimicrobials against test strains. Thus, the phytosynthesized NPs could be used as effective growth inhibitors for various microorganisms., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Terminalia arjuna (T. arjuna) bark extract is used to reduce Cu(2+)→Cu(0) under microwave irradiation. The formation of copper nanoparticles (CuNPs) is monitored by recording the UV-Vis absorption spectra for surface plasmon resonance (SPR) peak, ~535 nm. The intensity of SPR increased linearly with increasing temperature of the reaction mixture. The formation mechanism of CuNPs is supported by the observed marginal decrease in pH and an increase in solution potential (E) of the reaction mixture. X-ray diffraction (XRD) pattern of the CuNPs agrees with the reported data for Cu metal and the crystallite size is ~23 nm. Fourier transform infrared spectroscopy (FT-IR) and solid-state (13)C NMR shows the presence of plant residues on the CuNPs, i.e., in situ bio-capping is possible by this method. Thermo gravimetric (TG) analysis shows the thermal degradation of plant residue and the conversion of Cu to CuO. Field emission electron microscopic (FESEM) image shows uniform spherical particles obtained here. Elemental analysis by energy dispersive X-ray (EDX) analysis confirms the presence of Cu alone, as expected. The in vitro antimicrobial activity is found to be effective for CuNPs dried at RT when compared to CuNPs dried at 70 °C. In addition, CuNPs shows very good antioxidant property., (Copyright © 2013 Elsevier B.V. All rights reserved.)

A new series of La(1-x)Ce(x)CrO(3) (0.0